Blood tests have confirmed low B12 levels or you are experiencing symptoms suggestive of deficiency (fatigue, neurological symptoms, or anaemia)
There are more nerves in the muscle in the thigh than in the deltoid muscle, and it is easier to find the safe place to do the injection in the upper arm (which is why this is a common used place to give vaccinations i.m.)
Hoping this will give me energy
Most people with vitamin B 12 deficiency are treated in primary care with intramuscular (IM) vitamin B 12
What the evidence does support is this: B12 deficiency causes fatigue and neurological symptoms, and correcting deficiency in people who are deficient improves those symptoms
Methylcobalamin, a form of vitamin B12, is utilized in the treatment of various conditions such as neuropathy, anemia, B12 deficiency, megaloblastic anemia, and Leber's disease